In order to meet the demand for the protection of the interior trim of automobiles against deterioration, which has been increasing with the recent trend to luxury of the interior trim, and to reduce the load of air conditioning, green-tinted glass endowed with ultraviolet (UV) and infrared (IR) absorbing power has recently been proposed as window glass of automobiles.
For example, green-tinted glass having a UV transmission of not more than about 38%, a total solar energy transmission of not more than about 46% and, for securing an outside view, a visible light transmission of at least 70% is known. There is a tendency that green-tinted glass having a bluish green tint is preferred for use in automobiles.
It is known that reduction in total solar energy transmission can be achieved by increasing the absolute amount of ferrous oxide (FeO). This approach has been taken in most conventional IR-absorbing glasses.
Various proposals have hitherto been made with respect to reduction of UV transmission. For example, the green-tinted UV- and IR-absorbing glass disclosed in JP-A-3-187946 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") is characterized by containing cerium oxide and titanium oxide. In detail, the glass disclosed has a basic composition containing 65 to 75% by weight of SiO.sub.2, 0 to 3% by weight of Al.sub.2 O.sub.3, 1 to 5% by weight of MgO, 5 to 15% by weight of CaO, 10 to 15% of Na.sub.2 O, and 0 to 4% by weight of K.sub.2 O and contains, as coloring components, 0.51 to 0.96% by weight of Fe.sub.2 O.sub.3, a ratio of FeO based on the total iron oxide (hereinafter sometimes referred to as "FeO/T-Fe.sub.2 O.sub.3 ", where T-Fe.sub.2 O.sub.3 represents the total iron oxide in terms of Fe.sub.2 O.sub.3) of 0.23 to 0.29, 0.2 to 1.4% by weight of CeO.sub.2, and 0 to 0.85% by weight of TiO.sub.2.
The green-tinted UV-absorbing glass disclosed in JP-A-6-56466 comprises a soda-lime-silica basic glass composition containing, as coloring components, 0.53 to 0.70% by weight, in terms of Fe.sub.2 O.sub.3, of total iron oxide having an FeO/T-Fe.sub.2 O.sub.3 ratio of 0.30 to 0.40, 0.5 to 0.8% by weight of CeO.sub.2, and 0.2 to 0.4% by weight of TiO.sub.2.
The green-tinted UV-absorbing glass disclosed in JP-A-6-191880 comprises a soda-lime-silica basic glass composition containing, as coloring component, 0.75% by weight or more, in terms of Fe.sub.2 O.sub.3, of total iron oxide having an FeO/T-Fe.sub.2 O.sub.3 ratio of 0.22 to 0.29 and 0.8 to 1.2% by weight of CeO.sub.2.
However, glass endowed with UV absorbing power by introducing cerium oxide in a relatively high concentration as described above involves increased material cost due to the high cost of cerium sources.
In this regard, UV-absorbing glass having a reduced cerium oxide content has also been proposed. For example, JP-A-4-231347 discloses green-tinted UV-absorbing glass comprising a soda-lime-silica basic glass composition and containing, as coloring components, more than 0.85% by weight, in terms of Fe.sub.2 O.sub.3, of total iron oxide having an FeO/T-Fe.sub.2 O.sub.3 ratio of 0.275 or smaller and less than 0.5% by weight of CeO.sub.2.
The above-mentioned conventional UV- and IR-absorbing glass owes its UV absorbing characteristics to UV absorption by Fe.sub.2 O.sub.3, CeO.sub.2 and TiO.sub.2 and interactions among them. However, these components exhibit light absorption over a wavelength region not only including the UV region but extending to the visible region. Therefore, addition of these coloring components in an attempt to enhance UV absorption is accompanied by a reduction in transmission in the shorter visible wavelength region, resulting in yellowing of the glass.
The present invention has been made in the light of the above-described problems associated with the conventional techniques.